Equipment such as on and off highway vehicles, construction equipment, and generator sets may be powered by a main engine. In addition to the main engine, a battery may also be provided to assist in powering the equipment. Often times, the battery may supply the initial charge necessary to start the main engine, and may also supply other equipment components with electrical power. These other components may include amenities, such as, for example, radios, televisions, and/or heating and cooling devices.
Vehicle operators/drivers may power equipment components using power from the battery when the main engine is turned off. However, this may quickly drain the battery. The main engine may be turned on to supply the necessary power so that battery charge may be conserved for other processes, such as starting the main engine. Thus, vehicle operators/drivers may run the main engines on their vehicles for the sole purpose of providing power for heating and cooling to the operator's cab. Operating the main engine for this sole purpose may be inefficient in terms of fuel consumption. Using an auxiliary power unit (“APU”) may be a solution to this problem. It should be understood that APU may be referred to as a generator set (“gen-set”). The APU may include an auxiliary engine, separate from the main engine, which may supply power while the main engine is turned off. However, problems may still arise where vehicle operators/drivers draw power over the capabilities of the APU, requiring power from the battery, which may drain the battery, and in turn may lead to an inability to start the main engine.
At least one system has been developed to assist in assuring that the battery will have sufficient power for a main engine start. For example, U.S. Patent Application Publication 2005/0035657A1 to Brummett et al. (“Brummett”) describes a vehicle including an APU for operating an auxiliary air conditioning and heating system. In Brummett, a voltage regulator of the APU can selectively disable electrical components in the event that the voltage of a main battery drops below a selected level. After disabling an electrical component when the voltage of the main battery decreases below a first preselected voltage, the voltage regulator enables power back to the electrical component when the voltage of the battery exceeds a second preselected voltage higher than the first preselected voltage. While the system in Brummett has an APU that is capable of selectively disabling the powering of various electrical components, it does not have an APU that automatically starts to recharge the main battery to help prevent a no-start condition. Furthermore, the system of Brummett does not take into account the fact that low engine coolant temperatures may also prevent a main engine start even when the battery has sufficient power for a main engine start.
The present disclosure is directed towards overcoming one or more of the problems set forth above.